The USS John S. McCain guided-missile destroyer now bears the names of three men -- all of whom share exactly the same moniker.

It was originally named after John McCain's grandfather, Admiral John S. McCain Jr., who once headed the Pacific Command; and his grandfather, Admiral John S. McCain, who was a commander during World War II.

"Today, we add the story of Senator John S. McCain to the spirit of the mighty vessel which already carries the legacy of his father and grandfather," Navy Secretary Richard Spencer said at a ceremony aboard the vessel, which is docked at Yokosuka in Japan.

"As a warrior and a statesman who has always put country first, Senator John McCain never asked for this honor, and he would never seek it. But we would be remiss if we did not etch his name alongside his illustrious forebears."

McCain served in the Navy during the Vietnam War when, as an aviator, he was shot down and spent more than five years in captivity.

In a statement McCain, who is battling brain cancer, said he was "deeply honored" to be added to the name of the destroyer.

"My father and grandfather dedicated their entire lives to their naval service. The greatest honor of my life was to serve in the company of heroes," he said.

After retiring from the Navy, McCain entered politics, serving as a congressman and senator for Arizona.

Though he has not been seen in Washington for months, he still heads the influential Senate Armed Services Committee.

In 2008, he made a failed bid for the White House, when he ran alongside then Alaska governor Sarah Palin against Barack Obama.

The USS John S. McCain is currently undergoing repairs in Japan after it collided with a tanker on August 21, 2017, killing 10 sailors and injuring five others.